EXPLORING RECIPROCAL DIFFERENCES AND ASSESSMENT OF BREEDING POTENTIAL OF DOLICHOS BEAN (Lablab purpureus L.) CROSSES BASED ON TRANSGRESSIVE SEGREGATION AND USEFULNESS INDICES
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Date
2022-12-08, 2022-12-08
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University of Agricultural Sciences, Bangalore
University of Agricultural Sciences, Bangalore
University of Agricultural Sciences, Bangalore
Abstract
The plant breeders routinely attempt a large number of crosses including reciprocal crosses to generate variability to implement selection to identify superior recombinant inbred lines (RILs) for use as pure-line cultivars. Assessment of reciprocal cross
differences and breeding potential of crosses aids in the efficient use of limited resources by allowing early elimination of inferior crosses. This strategy increases the pace and efficiency of breeding dolichos bean, as is true in other crops. The combination of high quantitative traits (QTs) mean, absolute range (AR), standardized range (SR), absolute phenotypic variance (σ2p), phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV), transgressive segregation index (TSI) and usefulness index (UI) estimated in F2 and F3 generations was used as the criterion to assess and identify crosses with high breeding potential in terms of recovery of high frequency of RILs with desirable combinations of target traits. Presence/absence of significant differences in QTs mean, AR, SR, σ2p, PCV, GCV, TSI and UI between pairs of reciprocal crosses were considered as evidence for the presence/absence of reciprocal differences. Based on these criteria, the reciprocal crosses of HA 4 × HA 5 and HA 4 × GL 201 were comparable for all four traits, suggesting that crosses could be affected in any direction in dolichos bean. The breeding
potential varied with the trait and the statistics used. Hence, based on UI (a comprehensive quantitative measure), the cross HA 5 × HA 4 was identified more useful than the other crosses for grain weight plant-1.
The plant breeders routinely attempt a large number of crosses including reciprocal crosses to generate variability to implement selection to identify superior recombinant inbred lines (RILs) for use as pure-line cultivars. Assessment of reciprocal cross differences and breeding potential of crosses aids in the efficient use of limited resources by allowing early elimination of inferior crosses. This strategy increases the pace and efficiency of breeding dolichos bean, as is true in other crops. The combination of high quantitative traits (QTs) mean, absolute range (AR), standardized range (SR), absolute phenotypic variance (σ2p), phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV), transgressive segregation index (TSI) and usefulness index (UI) estimated in F2 and F3 generations was used as the criterion to assess and identify crosses with high breeding potential in terms of recovery of high frequency of RILs with desirable combinations of target traits. Presence/absence of significant differences in QTs mean, AR, SR, σ2p, PCV, GCV, TSI and UI between pairs of reciprocal crosses were considered as evidence for the presence/absence of reciprocal differences. Based on these criteria, the reciprocal crosses of HA 4 × HA 5 and HA 4 × GL 201 were comparable for all four traits, suggesting that crosses could be affected in any direction in dolichos bean. The breeding potential varied with the trait and the statistics used. Hence, based on UI (a comprehensive quantitative measure), the cross HA 5 × HA 4 was identified more useful than the other crosses for grain weight plant-1.
The plant breeders routinely attempt a large number of crosses including reciprocal crosses to generate variability to implement selection to identify superior recombinant inbred lines (RILs) for use as pure-line cultivars. Assessment of reciprocal cross differences and breeding potential of crosses aids in the efficient use of limited resources by allowing early elimination of inferior crosses. This strategy increases the pace and efficiency of breeding dolichos bean, as is true in other crops. The combination of high quantitative traits (QTs) mean, absolute range (AR), standardized range (SR), absolute phenotypic variance (σ2p), phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV), transgressive segregation index (TSI) and usefulness index (UI) estimated in F2 and F3 generations was used as the criterion to assess and identify crosses with high breeding potential in terms of recovery of high frequency of RILs with desirable combinations of target traits. Presence/absence of significant differences in QTs mean, AR, SR, σ2p, PCV, GCV, TSI and UI between pairs of reciprocal crosses were considered as evidence for the presence/absence of reciprocal differences. Based on these criteria, the reciprocal crosses of HA 4 × HA 5 and HA 4 × GL 201 were comparable for all four traits, suggesting that crosses could be affected in any direction in dolichos bean. The breeding potential varied with the trait and the statistics used. Hence, based on UI (a comprehensive quantitative measure), the cross HA 5 × HA 4 was identified more useful than the other crosses for grain weight plant-1.